Either too lean from the jet or slightly dirty carb not allowing full fuel flow at max load. If a main jet is at the bottom of the bowl then a 1 1/2 turns out from gently closed is the factory setting and 1 on the low idle. Going past 2 turns on the main jet would indicate someting is wrong with the carb. Usually 1/4 turn in or out from 1 1/2 smooths things out, mostly out. Some carbs have a big influence from the low idle and some have very little so you could check that also. 8-10 inches isn't that much for that machine to handle $#%*fortably.
Thanks for the reply. I will have to look at the carb again since I thought it was a fixed main jet, not adjustable. I feel that the low power is directly related to the lean condition though since the longer the run with max load, the worse it seems to be. As far as a dirty carb, it's possible but the machine only has about 8hrs run time since brand new.
Simplicity 990430 24" (vintage 1968)
Ariens ST1332LE 32"
